重庆降雨侵蚀力和侵蚀力密度对土壤侵蚀风险的评估

Assessment of Rainfall Erosivity and Erosivity Density on the Risk of Soil Erosion in Chongqing

研究重庆降雨侵蚀力(RE)和侵蚀力密度(ED)的时空变化,有利于开展土壤侵蚀防治和水土流失风险评估。利用1961—2020年重庆34个气象站的逐日降雨数据、TM遥感影像资料,采用日降雨侵蚀力模型、Mann-Kendall非参数检验、变异系数、克里金插值、叠加分析等方法,对降雨侵蚀力和侵蚀力密度进行时空分析,对重庆土壤侵蚀强度进行空间分析。结果表明:(1)重庆年平均降雨侵蚀力为5672.32(MJ·mm)/(hm^(2)·h·a),年平均侵蚀力密度为4.94 MJ/(hm^(2)·h·a),各季节平均降雨侵蚀力和侵蚀力密度的变化趋势基本一致;(2)年降雨侵蚀力和侵蚀力密度值均呈现渝东北最大,渝东南次之,渝西最小的规律。季节降雨侵蚀力和侵蚀力密度集中在夏季,表现为降雨侵蚀力渝东北最高,侵蚀力密度渝东最高;(3)重庆2020年土壤侵蚀强度以微度侵蚀为主,其次为轻度、中度、强度、极强度和剧烈侵蚀;(4)降雨侵蚀力、侵蚀力密度的侵蚀风险等级空间分布和土壤侵蚀强度等级空间分布相似,高值均出现在渝东北和渝东南地区。研究结果有助于管理者制定水土保持措施,有效防治重庆地区的水土流失。

Studying the temporal and spatial changes of rainfall erosivity(RE)and erosivity density(ED)in Chongqing is conducive to soil erosion control and soil erosion risk assessment.Using the daily rainfall data and TM remote sensing image data of 34 meteorological stations in Chongqing from 1961 to 2020,the daily rainfall erosion force model,Mann-Kendall nonparametric test,coefficient of variation,Kriging interpolation,superposition analysis and other methods were used to analyze RE and ED.The spatial and temporal analysis of soil erosion intensity in Chongqing was carried out.The results showed that:(1)Chongqing’s annual average rainfall erosivity was 5672.32(MJ·mm)/(hm^(2)·h·a),the annual average erosive force density was 4.94 MJ/(hm^(2)·h·a),and the variation trend of average rainfall erosivity and erosivity density in each season were basically the same.(2)The annual RE and ED were the largest in northeast Chongqing,the second in southeast Chongqing,and the smallest in western Chongqing.Seasonal rainfall erosivity and erosivity density were concentrated in summer,and the rainfall erosivity was the highest in northeast Chongqing,and the erosivity density was highest in eastern Chongqing.(3)The soil erosion intensity in Chongqing in 2020 was dominated by slight erosion,followed by mild,moderate,intensity,extreme intensity and severe erosion.(4)The spatial distribution of the erosion risk level of rainfall erosivity and erosivity density was similar to the spatial distribution of soil erosion intensity level,and the highest values were both in northeast and southeast Chongqing.The research results could help managers to formulate soil and water conservation measures to effectively prevent and control soil erosion in Chongqing.